This invention relates to turbochargers of the type used in cooperation with internal combustion engines, mainly compression ignition engines. In particular the invention relates to a turbocharger housing having a chamber for a turbine and having passageways in the housing for passage of exhaust gas and relates to a turbocharger which includes these elements as well as a wastegate and an EGR valve.
A turbocharger has a compressor located in the air intake system of an internal combustion engine in order to increase the amount of air and thereby also the fuel delivered to a combustion chamber to increase power output from an engine. The compressor is driven by a turbine located in the exhaust gas outlet and connected to the compressor by a shaft.
This has two advantages: 1) the engine is more efficient because it utilizes energy recovered from the exhaust gas flow and 2) a smaller engine can be made to produce a given power output.
The power available to drive the compressor is a nonlinear function of engine speed so that there is little boost at low speeds whereas at high speeds the boost is at a maximum. Most turbochargers are connected to a wastegate which enables exhaust gases to bypass the turbine, and which makes it possible to regulate the manifold pressure. The wastegate is typically controlled by a diaphragm that senses boost pressure.
In order to meet environmental considerations in relation to exhaust gases produced in the combustion chamber, turbochargers may also be included in an exhaust gas recycling (EGR) system where a percentage of the exhaust gases are recirculated through the combustion chambers. This is typically achieved by returning an amount of the exhaust gas to the inlet manifold.
Typically the engine exhaust manifold is made with connections to the turbocharger, EGR, and wastegate, and the turbocharger is made with corresponding connections. The EGR valve, and wastegate are bulky and all the associated connections are susceptible to leaking.
An object with the present invention is provide turbo charged engines with EGR valves and/or wastegate valves that neither requires a lot of space, nor is suseptible to leaks. Accordingly there is provided a turbocharger housing for an internal combustion engine which has a chamber for the turbine, an exhaust gas outlet downstream of the turbine chamber, exhaust gas inlets upstream of the turbine chamber and passageways to the turbine chamber and out the turbine chamber, including passageways or chambers for housing at least one wastegate and EGR valve.
By providing the turbocharger housing with at least one chamber and/or passageway for housing at least one of a wastegate and EGR valve the above mentioned objects will be accomplished. Preferably, the housing has a respective chamber and/or passageway for at least one wastegate, preferably two, and at least one EGR valve, preferably two EGR valves.
The two wastegate passageways may be connected to the turbine chamber exhaust gas outlet downstream of the wastegate location to form a single exhaust gas outlet port for exhaust gases exiting the housing.
The housing may further include a pair of exhaust gas inlet ports for the turbine chamber and each inlet port opens into a respective passageway for an EGR valve and a wastegate.
Also according to the invention there is provided a turbocharger for an internal combustion engine and which has a turbine driven by exhaust gases from the engine and includes integrally within the turbocharger at least one of a wastegate and EGR valve.
Yet a further aspect of the invention provides a method of installation on an internal combustion engine of a turbocharger, wastegate, and/or EGR valve.
Although a turbocharger housing according to the invention is more complicated than a conventional turbocharger housing, since the whole is supplied as a single unit it is easier to assemble to a vehicle during manufacture of the vehicle, and can be replaced during maintenance as a single unit. The invention will be described by way of example and with reference to the accompanying drawing.